1. Field of the Invention
This application is directed to economical solar generator systems.
2. Description of the Related Art
There is an enormous amount of solar energy provided by the sun that is available without significant environmental impact, or “green”. This energy is essentially free, in that it continually falls on the surface of the earth. The amount of energy impinging at any particular locale is a function of the geographic location, adverse atmospheric conditions, and season change. However, for many terrestrial locations, a great deal of solar energy impinges on the earth's surface every day. Unlike other sources of energy, solar energy does not require exploration, extraction of materials or refining.
Some efforts to harness this energy have been pursued, but with limited success. In one approach, photovoltaic (“PV”) devices, made of specialized silicon materials, are able to directly convert sunlight into electricity. Though simple and clean, even after years of development, PV devices remain quite expensive and cost prohibitive, resulting in long pay back periods. Also, PV devices produce relatively low voltage direct current (DC), which has generally limited PV devices to local use incompatible with using PV devices to support the grid.
Solar thermal is another branch of solar energy exploitation. This approach is similar to traditional electricity generation in that the energy of the sun drives a power plant, such that electricity is produced indirectly. Solar thermal efforts have focused on matching the efficiencies of traditional power plants that burn fossil fuels. Such efforts have required complex devices, such as focusing concentrating mirrors to heat oil to very high temperatures. In addition, very special oil handling structures are required, e.g., high performance seals to prevent leakage of the very high temperature oil. Although a few operating plants have been built, the cost of designing and building these plants is very high. Thus, these plants are not remotely economical and there is little, if any, return of investment. Because the economics do not justify these plants and because very few geographic locations are suitable, no economies of scale are available to make these plants more viable. These and other factors make traditional solar thermal plants economically unviable.
For at least these reasons, only a small fraction, currently less than one percent, of electricity produced in the United States exploits solar energy.